The present invention relates to a tape printing device.
Known tape printing apparatus of the type with which the present invention is generally concerned are disclosed in European Patents, EP-A-322918 and EP-A-322919 (Brother Kogyo Kabushiki Kaisha), and EP-A-267890 (Varitronics). These tape printing apparatus each include a cassette receiving bay for receiving a cassette or tape holding case. In European Patent EP-A-267890, the tape holding case houses an ink ribbon and a substrate tape, the latter comprising an upper image receiving layer secured to a backing layer by an adhesive. In European Patents, EP-A-322918 and EP-A-322919, the tape holding case houses an ink ribbon, a transparent image receiving tape and a double-sided adhesive tape which is secured at one of its adhesive coated sides to the image receiving tape after printing and which has a backing layer peelable from its other adhesive coated side. With both these apparatus, the image transfer medium (ink ribbon) and the image receiving tape (substrate) are in the same cassette.
A different type of tape printing apparatus is described a for example, in European Patents, in EP-A-578372. In this printing apparatus, the substrate tape is similar to that described in European Patent, EP-A-267890 but is housed in its own tape holding case while the ink ribbon is similarly housed in its own tape holding case.
The known tape printing apparatus have input means, generally a keyboard, to allow the user to input an image to be printed. A display is normally also provided to display the input image or messages to the user. A cutting arrangement is provided to separate the image receiving tape on which an image has been printed from the supply of image receiving tape to thereby define a label.
In these known tape printing apparatus, the image receiving tape passes in overlap with the ink ribbon through a print zone consisting of a fixed print head and a platen against which the print head can be pressed to cause an image to transfer from the ink ribbon to the image receiving tape. This is usually done by thermal printing where the print head is heated and the heat causes ink from the ink ribbon to be transferred to the image receiving tape. This type of printing is known as thermal transfer printing. Alternatively, the print head may be in direct contact with a thermally sensitive image receiving tape whereby when the print head is heated, an image is printed directly on the image receiving tape. This type of printing is known as direct thermal printing.
In European Patents EP-A-798121, such a tape printing apparatus is disclosed, wherein the motor for driving the image receiving tape through the printing zone is located above the tape cassette, and below the upper casing of the housing. The tape cassette is thus inserted from the bottom side. The keyboard is situated on the upper part of the housing, at the lower end. The batteries are located besides the cassette, and below a part of the keyboard, at its lower end. It is alleged that this arrangement reduces the size of the printer, and obtains a weight balance. The housing of this printer is generally cubic, wherein the upper part of the housing is somewhat inclined. Consequently, this tape printing apparatus is not a hand-held type, since it is too thick, but a desk top device.
In U.S. Pat. No. 5,435,657, a tape printer is used in combination with a slot-in type cassette. The printhead is privotally fixed to the housing of the tool and interacts with a platen provided in the cassette. Since the printhead is spring biased towards the platen, it is capable of urging the cassette out of the printer, when the latches holding the cassette are released. The housing is approximately cubic, as well.
U.S. Pat. No. 3,823,808 describes another tape cassette, which is used in combination with a pocket calculator, which prints inputted and calculated data onto a tape in order to dispense with a display. A tape cassette is provided with a planar platen interacting with a printhead fixed to the housing of the printer. Further, a feed roller is provided on the cassette, interacting with a roller of the machine in order to drive the tape out of the cassette. In order to make the printed data more easily visible to the user, the tape in the cassette is bent for about 45xc2x0 before printing. This device does not incorporate a display, but only a window through which the printed tape can be view.
European Patent EP-A-191495, refers to a desk-top thermal printer for printing labels provided on a label web. This printer comprises a housing with a brick-shaped bottom part incorporating a keyboard, wherein on its upper end an inclined portion is located, in which a display is provided. The printing mechanism is located in the upper part, behind the inclined portion. The batteries are located below the keyboard. The bottom part incorporates recessed portions for making it easier to hold the thermal printer in one hand while operating the keys of the keyboard with the other.
U.S. Pat. No. 5,626,428 discloses a tape printer with a keyboard having staggered keys, and a generally brick shaped housing, wherein the upper surface on which the keys are located is inclined with respect to the lower surface of the housing. The cassette is inserted from the bottom side.
U.S. Pat. Nos. 5,344,248 and 4,830,525 disclose desk-top printers with a hinged keyboard.
In British patent application 9717933.7, a hand held tape printer is disclosed, which has a single housing with a slim bottom part and a thicker top part. The top part houses the printing mechanism and the tape cassette, while the bottom part incorporates the batteries and the keyboard.
Thus, a number of tape printing devices are known in the art. None of them is however easily usable as a handheld tool, but as well suited for desk operation. It is therefore an object of the present invention to provide a tape printing device which is ergonomic and can be comfortably used in a multiplicity of positions.
According to a first aspect of the present invention there is provided a tape printing device for hand-held operation, having a housing with a first part and a second part, wherein:
the first part of the housing comprises a surface with a keyboard with keys for inputting desired characters to be printed onto an image receiving tape, the surface having a breadth which is larger than a thickness of the first part of the housing, preferably a multiple thereof;
and the second part of the housing comprises a cassette receiving bay for accomodating a tape cassette holding a supply of the image receiving tape, the second part of the housing further enclosing a print mechanism arranged to print the desired characters onto the image receiving tape.
The present invention thus proposes a tape printing device which consists of two parts. A first part contains a keyboard for defining characters to be printed onto a label, and a second part contains a tape cassette and the necessary print mechanism for printing an image onto the image receiving tape. Since the relatively large mechanical parts, as the print mechanism and the tape cassette are housed in the second part of the housing, the first part can be designed relatively slim. The thickness of the first part can be thus much smaller than its breadth. Hence, the breadth is measured over the lateral width of the keyboard, and the thickness is measured orthogonally thereto, i.e., in the direction in which the keys are depressed. Consequently, the tape printing device can be used ergonomically in a hand-held operation, but is suited for desk-top operation, as well.
The first part of the housing can also accomodate a space in which one or more batteries are accomodated. This has the advantage that the entire printing device is balanced, since the print mechanism and the cassette in the second part of the housing, and the batteries in the first part of the housing yield an equilibrium of torques, such that the device is ergonomic to handle.
For ergonomic reasons, it is further proposed that an angle is defined between the first part of the housing and the second part of the housing. In particular, the second part of the housing can be angled rearwards with respect to the surface of the first part of the housing in which the keyboard is located. The user can then hold the printing device in his or her palm, and depress the keys with his or her second hand whereby the device rests with the bottom face of the second part of the housing on the forefinger of the user. The angle between the first part of the housing and the second part of the housing is between 30 and 60xc2x0, preferably approximately 45xc2x0.
The cassette is preferably loaded from a top face of the second part of the housing.
Further, a display for displaying inputted characters can be provided, whereby it is proposed that the display is inclined with respect to the surface of the first part of the housing in which the keyboard is located, such that it is easily readable without disturbing reflections and gives a more pleasing viewing angle. The angle between the display and the surface is advantageously between 10xc2x0 and 80xc2x0, preferably approximately 30xc2x0.
A printed circuitboard cooperating with keys of the keyboard can be provided in the first part of the housing, and a second (main) printed circuitboard can be provided within the second part of the housing, the main printed circuitboard holding a controller operable to control the print mechanism and the display. Since the essential electronic parts are contained in the second part of the housing, the first part with the keyboard can be designed quite slim and thus user friendly. When all electronic components are thus removed from the printed circuitboard in the first part of the housing, it allows the circuitboard to be much cheaper material thereby saving unit cost.
A baseplate holding a motor, a platen roller and a print head holder with a printhead can be provided in the second part of the housing. The baseplate can be mounted to the main printed circuitboard, thus yielding a compact arrangement.
In order to reduce the volume of the print mechanism further, it is proposed that a motor is connected to a platen roller for driving the image receiving tape by at least one, preferably two worm gears and corresponding worm wheels. It should be noted that such a drive mechanism can be used in any tape printing device.
According to a second aspect of the present invention, there is provided a combination of a tape printing device and a tape cassette, wherein:
the tape printing device comprises a peel plunger,
the tape cassette comprises a housing in which a supply of tape is provided, and a peel slot arranged for accomodation of the peel plunger is defined within a side wall of the housing,
the tape comprises an adhesive covered image receiving layer and a backing layer, and a portion of the tape is located between the peel plunger and the peel slot,
and the peel plunger is arranged to move the tape into the peel slot,
characterized in that the longitudinal axis of the peel slot and the longitudinal axis of the tape enclose a non-perpendicular angle.
The second aspect of the present invention thus addresses the problem of peeling of tape, i.e., the separation of the image receiving layer and the releasable backing layer. In the prior art (European Patent EP-A-0634273 or EP-A-0526213), the plunger and the longitudinal axis of the tape are arranged to include an angle of 90xc2x0. Thus, peeling is performed by bending the tape over its entire width. Since a predetermined force is required for releasing the backing tape from the adhesive image receiving layer, and this force is proportional to the area in which peeling is performed, it is desirable to reduce this area in order to reduce the required force, or to improve the peeling result at a certain, available force. This aspect of the present invention thus proposes to have a non-perpendicular angle between the longitudinal axis of the peel plunger and the longitudinal axis of the tape (=feed direction). The angle can be between 30xc2x0 and 60xc2x0, preferably 45xc2x0. Since the peeled area is reduced, the peeling result is improved.